I'm using Windows 7 64bit Premium for two years now and in this time my C:\Windows folder has grown to almost 30GB which is, in my opinion, inacceptable.

The biggest subfolders are winsxs (10.5 GB), Installer (5.5 GB), System32 (4GB) and SoftwareDistribution(2.5GB). I googled for the winsxs folder and found that it's important and may not be deleted. I googled for the Installer folder and found that it's mostly Office-related and that it might be reduced a bit by deleting Office updates.

But that's not satisfying. Does it really take 27GB to have a working Windows 7 plus up-to-date Microsoft Office?

Is there any way to safely shrink the Windows folder (without having to reinstall Windows 7)?

  • Please note that this is not a duplicate, this is about %Windows% and not about %Windows%\winsxs. – Tamara Wijsman Jan 6 '12 at 20:59
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    winsxs is the Windows component store. All the Windows components in C:\Windows (including various subfolders including system32 and SysWOW64 for 64-bit systems), C:\Program Files, and some items in C:\ProgramData are all hardlinked from winsxs. If the tool you're using isn't hardlink aware (and TreeSize Free isn't, nor is Explorer itself), the information you're seeing is misleading at best and downright wrong at the worst. – afrazier Jan 6 '12 at 21:33
  • @afrazier Are Windows properties hardlink aware? The say 10GB too... – Baltram Jan 6 '12 at 21:47
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    No, the "Folder Properties" dialog is part of Explorer, and it's not hardlink aware in any way. Link Shell Extension can put an overlay icon on files with multiple hardlinks though. – afrazier Jan 6 '12 at 21:51

Apart from compressing the Backup folder in winsxs (in its properties); you can't make the winsxs much smaller, unless you very carefully inspect all the entries as well as whether these are dependencies for applications on your system. But that's a very tedious thing to do, so the best thing you can do about it is installing as much applications and Windows features in the hope for it to turn smaller. Or well, reinstall your system. Please note that this is normal behavior, also listed in the system specifications.

Likewise, the Installer folder contains all your .msi based installation packages. These are kept such that you can still repair or uninstall applications. You can safely compress this folder to gain some space, but don't remove it unless you are sure you never need to repair or uninstall all installed programs.

Everything in the SoftwareDistribution\Download folder can be deleted, these are just downloaded updates from Windows Update. This however might prevent you from being able to roll them back.

Also, regularly empty the C:\Windows\Temp folder if there's anything in there. You are supposed to use the Disk Cleanup wizard with Administrator privileges to do this, rather than doing it manually...

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    SoftwareDistribution\Download is perfectly safe to empty after a reboot. It's a download cache and nothing more. No rollback information is stored there. C:\Windows\Installer can be safely copied to another drive and the original replaced with a junction to the new location. – afrazier Jan 6 '12 at 21:34

Try running the following command from an elevated command prompt:

DISM /online /Cleanup-Image /SpSuperseded

Source: http://everythingsysadmin.wordpress.com/2011/03/16/cleanup-winsxs-after-windows-7-sp1-install



Leave it be. These are the installer files that are used if you go to "Add and Remove Software" and "Uninstall" or "Repair" software.


Run Disk Cleanup. Start Explorer, right-click on the C: drive, select Properties find and then click the Disk Cleanup button in the Properties window. Wait until the Disk Cleanup Window appears. Click "Clean up system files". Confirm and wait until the Disk Cleanup Window appears again. In "files to delete" check all boxes - make sure to scroll all the was through the list, there are ~9 items. Click "OK".


Run dism /online /Cleanup-Image /? from the command line. This will give you a list of commands to automatically clean up WinSxS in a safe way, and the implications of each command are spelled out.

First, you should have been running with this set of updates for at least a couple days, better a few weeks, so you know you do not want to roll back any of the updates.

You can then use

  • dism /online /Cleanup-Image /SpSuperseded
  • dism /online /Cleanup-Image /StartComponentCleanup (available on Windows 8, not on Windows 7)


  • dism /online /Cleanup-Image /StartComponentCleanup /ResetBase (available on Windows 8, not on Windows 7)

to reduce the size of WinSxS. Be sure to read about the side effects of these commands first by running dism /online /Cleanup-Image /?. You can read more about dism at technet.


I'm adding this one because it might be relevant to some people reading this answer: Look for Driverstoreexplorer (http://driverstoreexplorer.codeplex.com/). It's a tool to remove drivers that you don't need - after a few years there are usually a lot of them. Make sure to read up on what it does before you wrec your system. If you're not sure what it does, don't use it.

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    The original question was about Windows 7. I believe the /StartComponentCleanup option is only available in Windows 8 although Windows Update cleanup has been added to Disk Cleanup by support.microsoft.com/kb/2852386. – David Marshall Mar 12 '14 at 16:33
  • Just tested on a Windows 7 install, you're right. – Peter Mar 12 '14 at 16:37
  • The disk cleanup answer is still good. The first time I ran the Windows update cleanup option on Windows 7 I reclaimed about 2GB. With Windows 8.1, cleaning up WinSxS should be done automatically by the Maintenance task. – David Marshall Mar 12 '14 at 16:43

Try WinsxsLite, read about it here, do a full system backup before you run it.

Program here

  • The software in no longer available at either of the provided links. The google site refers to a dead rapidshare link. – Peter Mar 12 '14 at 15:42

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